From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 92CC5C5519F for ; Wed, 18 Nov 2020 16:04:33 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E74E420756 for ; Wed, 18 Nov 2020 16:04:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E74E420756 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:53706 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kfPwd-0007Dt-To for qemu-devel@archiver.kernel.org; Wed, 18 Nov 2020 11:04:31 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:45640) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kfPtj-0004bo-EK for qemu-devel@nongnu.org; Wed, 18 Nov 2020 11:01:35 -0500 Received: from foss.arm.com ([217.140.110.172]:50830) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kfPth-00089T-Ct for qemu-devel@nongnu.org; Wed, 18 Nov 2020 11:01:31 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 7AC33139F; Wed, 18 Nov 2020 08:01:28 -0800 (PST) Received: from [192.168.1.179] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B25AA3F719; Wed, 18 Nov 2020 08:01:25 -0800 (PST) Subject: Re: [PATCH v4 2/2] arm64: kvm: Introduce MTE VCPU feature To: Catalin Marinas References: <20201026155727.36685-1-steven.price@arm.com> <20201026155727.36685-3-steven.price@arm.com> From: Steven Price Message-ID: Date: Wed, 18 Nov 2020 16:01:20 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=217.140.110.172; envelope-from=steven.price@arm.com; helo=foss.arm.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/11/18 11:01:21 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Peter Maydell , "Dr. David Alan Gilbert" , Andrew Jones , Haibo Xu , Suzuki K Poulose , qemu-devel@nongnu.org, Marc Zyngier , Juan Quintela , Richard Henderson , linux-kernel@vger.kernel.org, Dave Martin , James Morse , linux-arm-kernel@lists.infradead.org, Thomas Gleixner , Will Deacon , kvmarm@lists.cs.columbia.edu, Julien Thierry Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 17/11/2020 16:07, Catalin Marinas wrote: > Hi Steven, > > On Mon, Oct 26, 2020 at 03:57:27PM +0000, Steven Price wrote: >> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c >> index 19aacc7d64de..38fe25310ca1 100644 >> --- a/arch/arm64/kvm/mmu.c >> +++ b/arch/arm64/kvm/mmu.c >> @@ -862,6 +862,26 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >> if (vma_pagesize == PAGE_SIZE && !force_pte) >> vma_pagesize = transparent_hugepage_adjust(memslot, hva, >> &pfn, &fault_ipa); >> + >> + /* >> + * The otherwise redundant test for system_supports_mte() allows the >> + * code to be compiled out when CONFIG_ARM64_MTE is not present. >> + */ >> + if (system_supports_mte() && kvm->arch.mte_enabled && pfn_valid(pfn)) { >> + /* >> + * VM will be able to see the page's tags, so we must ensure >> + * they have been initialised. >> + */ >> + struct page *page = pfn_to_page(pfn); >> + long i, nr_pages = compound_nr(page); >> + >> + /* if PG_mte_tagged is set, tags have already been initialised */ >> + for (i = 0; i < nr_pages; i++, page++) { >> + if (!test_and_set_bit(PG_mte_tagged, &page->flags)) >> + mte_clear_page_tags(page_address(page)); >> + } >> + } > > If this page was swapped out and mapped back in, where does the > restoring from swap happen? Restoring from swap happens above this in the call to gfn_to_pfn_prot() > I may have asked in the past, is user_mem_abort() the only path for > mapping Normal pages into stage 2? > That is my understanding (and yes you asked before) and no one has corrected me! ;) Steve